Looper mechanism for sewing machines



J. BERGER Dec. 31, 1929.

LOOPER MECHANISM FOR SEWING MACHINES Filed Oct. '16. 1926 3 Sheets-Sheet1 Dec. 31, 1929. J. BERGER LOOPER MECHANISM FOR SEWING MACHINES FiledOct. 16. 1926 3 Sheets-Sheet 2 Dec. 31, 1929. J. BERGER LOOPER MECHANISMFOR SEWING MACHINES Filed Oct. 16. 1926 3 Sheets-Sheet 3 Patented Dec.31, 1929 hurrah stares when PATENT @FFICE JOSEPH BERGER, OF UTICA, NEWYQRK, ASSIGNOR TO UNION SPECIAL MACHINE COM- PANY, OF CHICAGO, ILLINOIS,

A CORPORATION OF ILLINOIS LOOPER MECHANISM FOR SEVJING MACHINES Theinvention relates to new and useful improvements in a looper mechanismfor sewing machines, and more particularly a looper mechanism wherein athreaded looper cooperates with a plurality of needles.

An object of the invention is to provide a looper operating mechanismwherein the looper is moved at a relatively high speed and atsubstantially a uniform high speed while the point thereof is enteringeach one of the needle thread loops.

A further object of the invention is to provide a looper operatingmechanism of the above type wherein the looper is oscillated by aneccentric member on a rotating shaft.

A still further object of the invention is to provide a looper operatingmechanism of the above type wherein the Variable movement imparted tothe looper is accomplished by means of an oscillating arm moving about acenter eccentric to the center of the oscillating shaft carrying thelooper, and wherein said arm has a sliding connection with the loopershaft for oscillating the same, which sliding connection moves towardand from the center of the looper shaft for increasing the speed of thelooper at a predetermined time.

These and other objects will in part be obvious and will in part behereinafter more fully disclosed.

In the drawings which show by way of illustration one embodiment of theinvention Figure 1 is a side view of a machine embodying my improvedlooper operating mechanism, Fig. 2 is a sectional view on the line 2-2of Fig. 1;

Fig. 3 is a View, in part similar to that shown in Fig. 2, but showingthe looper operating eccentric at a difiercnt position in its rotation;

Fig. 4 is a sectional view 011 the line t-t of Fig. 1; l l

Fig. 5 is a sectional View on the line 5-5 of Fig. 3; I

Fig. 6 is a diagrammatic view showing the operating devices for thelooper with the looper shown at the forward end of itsstroke in fulllines, and at the rear end of its stroke in dotted lines;

Fig. 7 is a similar view, but showing the position of the parts when thelooper point is about to enter the needle thread loop of the firstneedle, and

Fig. 8 is a diagrammatic view showing three needles, and the looper, andindicating in broken lines the path of movement of the point of thelooper.

The invention is directed to a looper oper ating mechanism for amultiple needle sewing machine, wherein a thread carrying loopercooperates with all of the needles, entering first one needle threadloop and then another, and so on, with the other needles, if more thantwo needles are used. lit is preferably applied to a three-needlemachine for making a covering stitch used for seaming knit wear. it isdesirable to operate the looper by an eccentric member on the mainshaft, and when the eccentric member alone is used for operating thelooper, the looper will increase in its speed from its retractedposition to a point midway of its stroke. In the present invention, haveprovided de-" vices between the eccentric and the looper which cause thelooper to be speeded up just before the point enters the first needlethread loop to substantially its maximum speed, and the looper ismaiiiitaincd substantially at this speed until it is well into the lastneedle thread loop, after which it comes to the end of its stroke with adecreasing speed. I accomplish this variable speed in the looper bymeans of a swinging arm which is oscillated by the eccentric member.This arm is pivoted at a point eccentric to the aXis of the loopershaft. On the looper shaft are guides in which a bar can slide radiallyof the looper shaft, and the end of this bar is connected to the end ofthe arn'i, so that as the arm oscillates, it will oscillate the loopershaft.

Inasmuch as the bar slides radially in its connection to the loopershaft, it will be appar; cut that the point at which power is applied tothe looper shaft for oscillating the same moves in and out toward thecenter of the shaft. By properly positioning the arm relav tive to theaxis of the looper supporting shaft, I am able to increase the speed ofthe looper through the moving of the point of connection to the loopershaft toward the center thereof, just before the point of the looperenters the first needle loop, and to maintain this increased speed untilthe point of the looper is well into the last needle thread loop.

Referring more in detail to the drawings, I have shown the invention asapplied to a sewing machine which consists of a supporting standard 1carrying a housing 2 at its upper outer end, and this housing isprovided with a main operating shaft 3 which is retated by a belt wheela. Carried by the housing 2 is a depending member 5, and this dependingmember 5 carries a work supporting arm 6. A looper operating shaft 7 isjournaled in this work supporting arm, and on the end thereof is athread carrying looper 8.

The machine is provided with a needle bar 9 which is preferablyreciprocated by a lever connected to a crank on the main shaft 3, andsaid lever is so disposed relative to this shaft which actuates thesame, that the needle is given a more rapid upward movement than itsdownward movement. This greatly aids in the freeing of the from thematerial quickly to permit the feed of the material. This quick movementof the need e bar, however, is not essential to the present invention,but when such a structure is used for reciprocating the needle, it isquite essential that the looper shall be speeded up so as to get intothe three needle loops, if three needles are used, very quickly.

On the main shaft is an eccentric member 10 which as illustrated is inthe form of a crank, although some other type of eccentric member mightbe used. Connected to this crank is a link 11, and the link 11 is inturn connected to a ball stud 12 on the outer end of an arm 13. The armformed as a part of a yoke 14. The yoke it has two sleeves 15 and 16which are in alinement. and a short stub shaft 17 is secured to thesleeve 16 by a screw 18, while a short stub shaft 19 is secured to thesleeve 15 by sa'ew 20. These shafts 17 and 19 are mounted in suitablebushings carried by the frame of the machine. This forms a support whichpct:- mits the arm 13 to oscillate about the center of the shafts 17and. 19 an axis. As the crank rotates. the arm 13 will be oscillated.

The looper shaft 17 is provided with a head 21 which is formed with aradial channel 22. A bar 23 is located in this channel, and the outerend of the bar 23 is connected to the outer end of the arm 13 at 24. Theshank of the ball stud 12 may extend through the arm 13 and serve as aconnection for this bar 23-. Vhen the arm 13 is oscillated, the ballstud 12 will, of course, move in the arc of a circle about the center ofthe shaft 17 as an axis. Inasmuch as this axis is eccentric to thecenter of oscillation of the looper shaft, the ball stud 12 will movetoward the axis of the looper shaft on the first part of its downwardmovement, and this will cause the bar 23 to slide in the channel head,and the point of connection to the looper shaft for oscillating the samemoves toward the axis of the looper shaft. It will be apparent that ifthe ball stud had a uniform speed of travel, this inward movement of theball stud toward the axis of the looper shaft would increase the speedof the looper as the arm. 13 oscillates. As soon as the ball stud 12passes a line passing through the axis of the looper shaft, and the axison which the arm 13 oscillates, then the ball. stud will move out awayfrom the axis of the looper, and the bar 23 will slide outward to permitthis movement. The diagrammatic views in Figures 6 to 8 will possiblymake the invention more clear. In Fig. 8, three needles n, n and n areshown, and cooperating with these three needles is the thread carryinglooper 8. This thread carrying looper is of the usual type and is movedinto the needle thread loops, then laterally to avoid the needle, and isthen retracted out of the needle thread loops in the usual manner, sofar as concatenation of the looper and needle threads is concerned.

It will be apparent from Fig. 8, that the looper point enters first theloop of thread of the needle n, then the loop of thread of the needle n,and then the loop of thread of the needle 71/. The needles are set atdifferent heights, as is customary in this type of machine, to aid inthe looper engaging all three loops, one after the other. This. however,is not quite sufiicient in a high speed machine, and the presentinvention is directed to means for speeding up the looper when the pointthereof reaches the position indicated at b in Fig. 8. The looper pointwhen completely retracted is at the point a, and when at the end of itsforward reciprocation, it is at the point (l. The present mechanismincreases the speed of the looper, beginning substantially at the pointZ) in its path of travel, and the speed is maintained at a substantiallyuniform high speed, until the point 0 is reached, where the looper iswell into the needle thread loops. When the looper point is at the pointa in its path of travel, that is, completely retracted, the crank 10 isat the broken line position in Fig. 6, and when the looper is at theforward end of its stroke, then the crank is at the full line positionshown in this figure. Starting with the crank in the broken lineposition in this figure, it will be noted that as the crank rotates, thearm 13 approaches the line at, m, where the ball stud is in alinementwith the axis of the looper shaft and the shaft 17 which supports thearm 13. During this time, the ball stud is moving closer to the centerof the looper shaft, and the bar 23 is sliding radially to permit thismovement.

Therefore, the speed of the looper point is increasing by reason of theinward move ment of the ball stud-toward the axis of the looper shaft.The speed of travel of the link 11 is also increasing as the crank 10increases in its speed of movement in a direction lengthwise of the link11 until it has passed through an arc of substantially ninety degrees,or has reached the point indicated at e in Fig. 6 of the drawings. Theincreased speed due to the inward movement of the ball stud toward thecenter of the looper shaft, is therefore, added to the increase of speedof the link 11 imparted thereto by the crank 10. When the point of thelooper, therefore, is about to enter the first needle thread loop, thespeed of the looper point is increased well up to its maximum. The

crank 10 is substantially at the position 7 indicated in Fig. 6 when theball stud is at the line ac, m. After the ball stud passes the line at,m, then said ball stud will move away from the center of the loopershaft, and

would tend to decrease the speed of the shaft, but the crank 10 ismoving from the point on toward the point e in its circular travel andapproaching the point of highest speed which it imparts to the link 11.Therefore,

the speed of the point of the looper will be entered the needle threadloop of the last needle and is well into the same, then the speed of thelooper will decrease, owing to the fact that the crank is moving fromthe point e in Fig. 6 to the position indicated in full lines in thedrawings, and the ball stud is continuing to move away from the centerof the looper shaft.

Of course, the retracted movement of the looper will also have avariable speed similar to that of its forward movement. This enables theneedles to move down into the triangle formed in the looper thread,after which the needle thread loops on the looper may be quickly shedfrom the looper. The particular advantage, however, of the looperoperating mechanism is in the movement of the looper quickly into theneedle thread loops.

From the above it will be apparent that I have provided a looperoperating mechanism wherein the power utilized for oscillating thelooper is derived from a rotating eccentric member, and the devicesintermediate this rotating eccentric member and the looper are soconstructed as to impart a variable movement to the looper, and givethereto a substantially uniform high speed during the entire time thatthe looper point is passing into the needle thread loops in succession.That is, from the time it is closed to the'first "needle thread loopuntil it has passed clear through the last needle threadloop.

From the above it will be apparent that I have provided a loopermovement which is especially adapted for use in a sewing machine havinga cylindrical work supporting arm of small diameter. In such a machine,the radius of the looper must be relatively short as compared with whatthe radius might be in larger cylinders or flat bed machines.Notwithstanding the small, radius of the looper, it is necessary tomaintain or increase the speed of the looper, so that the looper willproperly cooperate with all three needles. This increased speed of thelooper permits the points of the needles to be brought very closetogether.

It is obvious that minor changes in'the details of construction may bemade without departing from the spirit of the invention as set forth inthe appended claims.

Having thus described the invention, what I claim as new and desire tosecure by Letters-Patent, is I 1. The combination of a plurality ofthreaded needles, a thread carrying looper 00- operating with saidneedles, means for oscillating said thread carrying looper including arotating eccentric member, a link connected thereto, a pivoted armattached to said link and oscillated thereby, a shaft on which saidlooper is mounted, said shaft being set eccentric to the pivotal pointof said arm, and so that as said arm oscillates, it will move relativeto and across the axis of the looper shaft, and means for connectingsaid arm to said looper shaft.

2. The combination of a plurality of threaded needles, a thread carryinglooper cooperating with said needles, means for oscillating said threadcarrying looper including a rotating eccentric member, a link connectedthereto, a pivoted arm attached to said link and oscillated thereby, ashaft on which said looper is mounted, said shaft being set; eccentricto the pivotal point of said arm,

and so that as said arm oscillates, it will move across the axis of thelooper shaft, and means for connecting said arm to said looper shaft,said last-named means including a bar piv oted to said arm and having asliding con nection with the looper supporting shaft.

3. The combination of a plurality of threaded needles, a thread carryinglooper cooperating with said needles, means for os cillating said threadcarrying looper including a rotating eccentric member, alink con nectedthereto, a pivoted arm attached to said link and oscillated thereby, ashaft on which said looper is mounted, said shaft being set eccentric tothe pivotal point of said arm, and so that as said arm oscillates, itwill move across the axis of the looper shaft, means for connecting saidarm to said looper shaft, said last-named means including a headcarried;

at the end of the looper operating and having a radial channel therein,and a bar slidable in said channel and pivoted to said arm adjacent theouter end thereof.

4. The combination of a plurality of threaded needles, a thread carryinglooper cooperating with said needles, a shaft on which said threadcarrying iooper is mounted, means for oscillating said shaft including arotating eccentric member, a link connected thereto, a pivoted yokehaving an extended arm to which the link is connected, whereby therotations of said eccentric member oscillate said arm, the axis of saidpivoted yoke being disposed on the opposite side of the axis of theshaft from the free end of the arm, and so that said arm moves acrossthe axis of the looper shaft in its oscillations, and a bar pivotallyconnected to said arm adjacent the outer end thereof having a slidingradial connection with the looper shaft so that the oscillations of saidarm through said bar impart oscillations to said looper shaft.

5. The combination of a plurality of threaded needles, a thread carryinglooper cooperating with said needles and entering the needle threadloops in succession, a shaft on which said looper is supported, a memberconnected to said shaft for oscillating the same, said member beingshiftable radially of the shaft during the oscillations thereof, meansconnected to said member for oscillating the same, and a deviceconnected to said member for shifting the same during the os- 3'cillation of the shaft, whereby the looper is given a substantiallyuniform relatively high speed movement Where the point is entering allof the needle thread loops.

In testimony whereof, I aflix my signature.

JOSEPH BERGER.

